If you could get a csv file of the reviews you could possibly import them using the CSV file import button on the Review List page. You would need to manually enter a review first, then download the CSV file, then copy and paste your etsy reviews in to that CSV file. That way it would be in the correct format when you uploaded it back in.
I'm working to update the app to include an automated download, but it's pretty far off.
Ideas
If you could get a csv file of the reviews you could possibly import them using the CSV file import button on the Review List page. You would need to manually enter a review first, then download the CSV file, then copy and paste your etsy reviews in to that CSV file. That way it would be in the correct format when you uploaded it back in.
I'm working to update the app to include an automated download, but it's pretty far off.